Neutron sources are used in a variety of applications, including oil and natural gas exploration. Currently available commercial neutron sources contain finely divided powders comprising a radioactive material, e.g., 241AmO2, and beryllium metal, which are mixed together to provide intimate contact between the materials. In natural gas and oil exploration, “logging” wells (i.e., determining characteristics such as density, porosity, and attenuation, among others) is an important step in predicting production potential. Logging may be performed by “wire line,” in which the neutron source is placed in an open or cased hole, or alternatively logging may be performed while drilling, in which case the neutron source and detector(s) are placed on a special section of the drilling stem. In some instances, neutron sources may be lost or damaged during the process. In order to prevent accidental dispersion, the powdered material is encased in multiple welded capsules, however, the capsules are not always strong enough to prevent accidental dispersion. In addition, in recent years, concerns about intentional dispersion have increased. Whether accidental or intentional, once a powdered substance is dispersed, containment and cleanup become difficult (if not impossible) and expensive.
A need exists, therefore, for neutron sources which comprise an AnBe material which is less dispersible, and which provides a steady, reliable source of neutrons.